Preconception Folate and Vitamin B6 Status and Clinical Spontaneous Abortion in Chinese Women

Abstract

In Brief OBJECTIVE To assess the association between preconception homocysteine and B vitamin status and risk of clinical spontaneous abortion in women from Anqing, China. METHODS All women were aged 21–34 years, had never smoked, and were primigravid. Patients (n = 49) were women with a clinically recognized pregnancy who experienced a fetal death before 100 days' gestation. Controls (n = 409) were women who maintained a pregnancy that ended in a live birth. Homocysteine, folate, and vitamins B6 and B12 concentrations were measured in plasma obtained before conception. RESULTS Mean vitamin B6 concentration was lower in patients than in controls (34.0 versus 37.9 nmol/L, P = .04). In addition, the risk of spontaneous abortion tended to increase with decreasing plasma vitamin B6 and folate concentration (P for trend = .06 and .07, respectively), although the significance of these trends was further reduced in logistic models that included age, body mass index, and both vitamins. The risk of spontaneous abortion was four-fold higher among women with suboptimal plasma concentrations of both folate and vitamin B6 (folate less than or equal to 8.4 nmol/L and vitamin B6 less than or equal to 49 nmol/L) than in those with higher plasma concentrations of both vitamins (odds ratio 4.1, 95% confidence interval 1.2, 14.4). Homocysteine and vitamin B12 status were not associated with spontaneous abortion risk. CONCLUSION Suboptimal preconception folate and vitamin B6 status, especially when they occur together, may increase the risk of clinical spontaneous abortion. Additional prospective studies are needed to confirm these findings and to determine whether antenatal B vitamin supplementation reduces spontaneous abortion risk. Suboptimal prepregnancy folate and vitamin B6 status may be associated with increased risk of clinical spontaneous abortion in young Chinese women.